I've noticed of the last few days that there is an increased amount of threads complaining about wrist pain. Post some suggestions in here to be added, so there can be a list of possible answers to these problems. Here are the first two suggestions.
1)Loosen up that death grip. You are not going to die if you fall off the bike. Just get a grip on the grips just enough that you can control the bike. A death grip puts alot of strain on the muscles and ligament connecting the wrist to the hand. Most cycling related cts cases are with people who always ride with a death grip on the handle bars.
2)Loosen up the arms in general. Put some trust in soaking up the rough stuff with the legs the legs can take more abuse than the arms can, when through this rough stuff, stay loose, let the bike go in the direction it's going in, worry about correcting the direction when your out of the rough section. Same goes with smooth surfaces keep the arms loose, keep arms and legs loose when landing a drop or jump.